Lunar Eclipse Essentials

Released on June 8, 2011

When the moon passes through the Earth's shadow, it causes the moon to look very unusual for a short period of time. This event is called a lunar eclipse, and it occurs roughly twice a year. Learn more about how lunar eclipses work in this video!

These videos and animations are available in both standard formats as well as stereoscopic 3D for those who can view it. We've included left and right eye clips, a side-by-side version, and an anaglyph (red/blue) version of the narrated video, and left and right eye clips for each of the animations. The labels next to each link will help you pick!

ANIMATION - LUNAR ECLIPSE FEATURES: During a lunar eclipse, the moon passes through the Earth's shadow, which can be divided into two parts. When it passes through the penumbra, the moon only gets slightly darker. When it passes through the umbra, however, it darkens further and turns a deep red.

ANIMATION - LIGHT SCATTERED BY THE EARTH'S ATMOSPHERE: As light passes by the Earth's atmosphere, short wavelengths, like blue, are scattered. By the time light finishes its trip to the moon, only longer wavelengths, like red, remain. This is why the moon turns red during an eclipse! Credit goes to TheWusa from de.wikipedia.org for the illustration this animation is based on.

ANIMATION - LIGHT SCATTERING SEEN FROM THE MOON: The way that light is scattered by the Earth's atmosphere to turn the moon red during an eclipse is similar to how the sky turns red at sunset. Credit goes to TheWusa from de.wikipedia.org for the illustration this animation is based on.

ANIMATION - ECLIPSE VIEWED FROM EARTH: When you see an eclipse from Earth, the moon gets darker and turns a deep red before eventually returning to its normal color. The process can last anywhere from a few minutes to a few hours.